If RVB values should be given, what reference space should be considered? The spaces are too numerous, their use specific, it will be impossible to furnish measures data of the charts for each space. L.a.b space is universal and is dependent from no any colorimetric space: that’s the reason of the choice of the L.a.b values provided at the back of the chart.

Yes. The chart can be used with Raw as well with Jpeg. It accepts the 2 data formats. Moreover, the Raw format is the more adaptable format for managing white balance on post-production, it will be the format which offers the best results.

No. The grey of the TrueColors chart isn’t the same as the famous Kodak chart. The 18% grey is darker and can lead to more “numeric noise” in the signal. It can diminish efficiency of the correction.
The Kodak chart is optimized for exposition setting; the TrueColors is optimized for white balance (lighter, the noise-signal ratio is better).

Yes. The flashlight has often a blue tone (We used to say that it “cool down” the picture). The chart will permit to correct this blue dominant. It is more obvious if you are shooting on indirect flash, the use of the chart will permit to correct any colored dominant.

Of course, it is possible to use white balance to a “creative” goal. It is completely justified to prefer hotter or colder tonalities in a picture. But technically, it is interesting to begin with a correct balance then to apply a colored dominant to the image. Imagine a pneumatic inflating …when the right pressure is obtained, you decide to adapt inflating to the use or the conditions. It is the same thing for the white balance of your images.